1. Field of the Invention
This invention relates to a bicycle, more particularly to a bicycle that includes a drive sprocket disposed in front of a seat tube so as to shorten the total length of the bicycle.
2. Description of the Related Art
A conventional bicycle includes a drive sprocket and a crank that are disposed under a seat tube. As there is a need to space the drive sprocket from a driven sprocket by an appropriate distance in order to smooth running of a chain trained on the drive and driven sprockets, the conventional bicycle is relatively long, thereby resulting in difficulties when the bicycle is transported or stored.
The object of this invention is to provide a bicycle, which includes a drive sprocket disposed in front of a seat tube, so as to shorten the total length of the bicycle.
According to this invention, a bicycle includes a bicycle frame, a wheel unit, and a transmission. The bicycle frame includes an upright head tube, an upright seat tube, and an inclined main tube that has a front end which is connected fixedly to the head tube, and a rear end which is connected fixedly to the seat tube and which is located below the front end. The main tube extends rearwardly and downwardly from the head tube to the seat tube. The wheel unit includes a front wheel mounted rotatably on a front end of the bicycle frame, and a rear wheel mounted rotatably on a rear end of the bicycle frame and having a diameter greater than that of the front wheel. The transmission includes: a drive sprocket disposed rotatably on the main tube and located between the head tube and the seat tube; a crank disposed rotatably on the main tube and connected coaxially and fixedly to the drive sprocket, the crank having two crank arms; two pedals mounted respectively and rotatably on the crank arms; a driven sprocket connected coaxially and fixedly to the rear wheel; and a chain trained on the drive and driven sprockets so as to transfer rotation of the drive sprocket to the driven sprocket.